1. Mario Chalmers can't guard him. Chalmers is a serviceable defender, but not a great one. The Heat will be ecstatic if he can guard Westbrook without fouling for significant minutes. But they can't expect Chalmers to contain him in any meaningful way.

2. Dwyane Wade isn't himself. The D-Wade of old could have held his own against Westbrook (or at least made him turn the ball over). But Wade has been hurt all playoffs, and there's just no way he can stay with Westbrook off the dribble at this point.

3. Westbrook's penetration can destroy Miami's help defense and create open threes. Miami's primary defensive weakness is guarding the perimeter. If Westbrook can get into the lane at will, the Heat will be forced to collapse — which will be disastrous because it'll lead to threes from solid distance shooters like Durant, James Harden, Daequan Cook, and Thabo Sefolosha.

4. LeBron James is the perfect defender to stop Kevin Durant. You aren't going to see LBJ guarding Durant all game (he'd get gassed). But if you could build a defender in a lab to stop Durant, it'd be LeBron. He's strong enough to push KD away from the basket. He's quick enough to stay in front of him off the dribble. And he's long enough to bother Durant's jump-shooting.

Miami has a very simple answer to Durant. But they don't have one for Westbrook.